Carbon blacks having low PAH amounts and methods of making same

ABSTRACT

Carbon blacks, such as rubber blacks, having a low PAH concentration are described. Furthermore, elastomeric or rubber compositions containing the carbon black of the present invention are further described, as well as methods of making carbon black having a low PAH concentration.

This application claims the benefit under 35 U.S.C. §119(e) of priorU.S. Provisional Patent Application No. 60/864,750, filed Nov. 7, 2006,which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to carbon blacks, compositions containingthe carbon blacks, such as elastomeric or rubber compositions, methodsof making the carbon blacks, as well as methods of using the carbonblacks.

Industrially manufactured carbon black is produced by pyrolysis ofhydrocarbons at high temperatures under controlled process conditions.Under these conditions, trace levels of polyaromatic hydrocarbons, alsoknown as PAHs, form on the carbon black surface.

Some PAHs have the potential to cause adverse health effects. Althoughthe PAHs that are adhered to the carbon black are not readily availablefor human exposure, actions are being taken by both EU regulators andcustomers to reduce the concentration of PAHs in carbon black (See BormP J, et. al., Formation of PAH-DNA adducts after in vivo and vitroexposure of rats and lung cells to different commercial carbon blacks,Toxicology and Applied Pharmacology, 2005 Jun. 1; 205(2): 157-167.).Recent examples include:

-   -   Promulgation of EU directive 2007/19/EC which harmonizes the        rules for the plastic materials and articles intended to come in        contact with food. The directive establishes a Benzo(a)pyrene        content of 0.25 mg/kg in carbon black. Previous to this        directive, no PAH limit existed for carbon black.    -   Promulgation of EU directive 2005/69/EC which regulates the        content of PAHs in extenders oils used for the production of        tires. This directive does not directly regulate the content of        PAHs in carbon black; however, the EU has chosen to restrict the        content of PAHs in extender oils and blends used to produce        tires, in order to reduce the total annual emissions of PAHs, as        required in the 1998 Protocol to the 1979 Convention on Long        Range Transboundary Air Pollution on Persistent Organic        Pollutants.

The above listed examples demonstrate the growing trend towards lowerPAH carbon blacks.

While there is a growing desire to have lower PAHs for carbon blacks,any reduction in PAH cannot compromise the desirable performanceproperties of carbon black in rubber and other applications. Thus, it isdesirable to reduce PAH concentration in carbon black withoutsacrificing the properties achievable by the current carbon blacks.

SUMMARY OF THE PRESENT INVENTION

A feature of the present invention is to provide carbon blacks havinglow PAH amounts.

A further feature of the present invention is to provide carbon blackshaving low PAH amounts which retain acceptable physical properties inrubber and other applications.

A further feature of the present invention is to provide methods ofmaking carbon blacks having low PAH amounts.

An additional feature of the present invention is to provide rubberblacks having desirable rubber properties, and yet having low PAHamounts.

Additional features and advantages of the present invention will be setforth in part in the description that follows, and in part will beapparent from the description, or may be learned by practice of thepresent invention. The objectives and other advantages of the presentinvention will be realized and attained by means of the elements andcombinations particularly pointed out in the description and appendedclaims.

To achieve these and other advantages, and in accordance with thepurposes of the present invention, as embodied and broadly describedherein, the present invention relates to a carbon black having a low PAHamount, such as a low total concentration for a defined group of 22 PAHcompounds (see FIG. 1). For purposes of the present invention, the PAH22is a measurement of the PAHs identified in FIG. 1 except forBenzo(j)fluoranthrene. Also, the PAH8 for purposes of the presentinvention is a measurement of Benzo(a)anthracene, Benzo(a)pyrene,Benzo(e)pyrene, Benzo(b)fluoranthrene, Benzo(j)fluoranthrene,Benzo(k)fluoranthrene, Chrysene, and Dibenzo(a,h)anthracene. BaP is areference to Benzo(a)pyrene. For instance, the carbon black can have alow total concentration for the 22 PAHs on the order of 500 ppm or less,such as 300 ppm or less, 100 ppm or less, or 75 ppm or less, or 30 ppmor less.

The present invention further relates to elastomeric or rubbercompositions containing at least one carbon black of the presentinvention in the elastomeric or rubber composition along with at leastone elastomer or polymer or rubber.

The present invention also relates to a method of making carbon blackshaving a low PAH total concentration which includes the step ofsubjecting the carbon black to sufficient heat to remove at least aportion of the PAHs from the carbon black and/or subjecting the carbonblack to a solvent extraction to remove at least a portion of the PAHsfrom the carbon black. The present invention also relates to a method toproduce carbon black having low PAR amounts, wherein duringmanufacturing of carbon black involving the presence of hot tail gascontaining a carbon black and PAH, the method comprises removing the hottail gas (or at least a portion thereof) with PAH from the carbon black.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are intended to provide a further explanation of the presentinvention, as claimed.

The accompanying drawings, which are incorporated in and constitute apart of this application, illustrate some of the embodiments of thepresent invention and together with the description, serve to explainthe principles of the present invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a table of 22 PAH compounds (except for Benzo(j)fluoranthrene)which are considered the “PAH 22” for purposes of the present invention.

FIG. 2 is a graph showing PAH 22 versus Treatment Temperature.

FIG. 3 is a bar graph showing total PAH for three samples, one of whichhas a low total concentration of PAH.

FIG. 4 is a bar graph showing relative rubber properties for the threesamples.

FIG. 5 is a diagram showing an example of a cyclone recovery system.

FIG. 6 a-c are graphs showing the reduction of naphthalene, coronene,and total PAH 22 content that are reduced in a VULCAN 7H carbon blackover a variety of temperature.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention relates to carbon blacks having a low PAH amount,such as a low PAH 22. The present invention also relates to rubbercompositions or elastomeric compositions containing at least one carbonblack of the present invention, along with at least one elastomer. Thepresent invention further relates to methods of making the carbon blacksof the present invention.

In at least one embodiment of the present invention, the presentinvention relates to a carbon black having a low PAH amount. The carbonblack can be formed so that the carbon black has a low PAH amount orcommercially-available carbon black can be properly treated to removePAHs so as to form carbon blacks having a low PAH amount. The carbonblack of the present invention can have a low PAH amount with anystandard ASTM carbon black specifications, for instance with respect toiodine absorption, DBPA, crushed DBPA, CTAB, nitrogen surface area,STSA, and/or tinting strength, and the like. The carbon black can be anASTM specification carbon black, such as a N110, N121, N220, N231, N234,N299, N326, N330, N339, N347, N351, N358, N375, N539, N550, N650, N660,N683, N762, N765, N774, N787, and/or N990 carbon black, which has theASTM specification properties for the particular N-series carbon black.The carbon black can have a STSA ranging from 20 m²/g to 150 m²/g orhigher. The carbon black can be any ASTM grade carbon black having thelow PAH amount, such as from a N110 ASTM carbon black to a N990 ASTMcarbon black and more preferably a N 110 to N500 ASTM carbon black. Anycommercial grade of carbon black can be formed to have a low PAH amountand/or can be subsequently treated to have a low PAH amount based on thepresent invention. The carbon black can be a furnace black, channelblack, lamp black, thermal black, acetylene black, plasma black, acarbon product containing silicon-containing species, and/or metalcontaining species and the like.

In at least one embodiment of the present invention, the presentinvention relates to one or more carbon blacks having a low PAH amount(for purposes of the present invention, the PAH content ismeasured/tested by the method described at 21 CFR part 17B, FDA FederalRegister, v62, #90. Friday May 9, 1997, incorporated in its entirety byreference herein) and, optionally, has the ability to impart at leastone beneficial mechanical property in a rubber matrix, or an elastomericcomposition. The at least one beneficial mechanical property can be oneor more of the following:

-   -   abrasion resistance (21% slip)—tested per U.S. Pat. No.        4,995,197.    -   elongation (%)—ASTM D 3191-02 Standard Test Methods for Carbon        Black in SBR—Recipe and Evaluation Procedures.    -   tensile strength (Mpa); ASTM D 3191-02 Standard Test Methods for        Carbon Black in SBR—Recipe and Evaluation Procedures.    -   100% modulus (Mpa); ASTM D 3191-02 Standard Test Methods for        Carbon Black in SBR—Recipe and Evaluation Procedures.    -   300% modulus (Mpa); ASTM D 3191-02 Standard Test Methods for        Carbon Black in SBR—Recipe and Evaluation Procedures.    -   ratio of 300% modulus/100% modulus (M300%/M100%); ASTM D 3191-02        Standard Test Methods for Carbon Black in SBR—Recipe and        Evaluation Procedures.    -   bound rubber (%); S. Wolff, M-J Wang, E-H Tan, Rubber Chem        Techn, v 66, 163 (1993).    -   max tan delta @ 0° C. tested with ARES/Rheometrics Dynamic        Spectrometer TI (RDS II, Rheometrics, Inc., N.J.) operated in a        torsion strain mode (shear). The measurements were performed at        0° C. for strain sweeps with double strain amplitude (DSA)        ranging from 0.2 to 120%, at a constant frequency of 10 Hz.

In one or more embodiments of the present invention, the carbon black ofthe present invention can have a low PAH amount and at least one ofthese beneficial mechanical properties, at least two, at least three, atleast four, at least five, at least six, at least seven, and/or alleight of these beneficial mechanical properties. These mechanicalproperties are measured by known ASTM or published standards, which areprovided next to each mechanical property above.

In at least one embodiment of the present invention, the presentinvention relates to a carbon black having a low PAH amount, such as alow PAH 22, wherein the carbon black has the ability to impart at leastone beneficial mechanical property, as described above, wherein at leastone of these mechanical properties is within 10% (e.g., within 5%,within 3%, within 1%) of the value for the same mechanical property forthe same type of carbon black, having a high PAH, such as a high PAH 22.A high PAH 22 can be, for instance, 600 ppm or higher, such as 600 ppmto 1,000 ppm of PAH 22. The carbon black of the present invention, whichhas a low PAH amount and the ability to impart at least one beneficialmechanical property in a polymer matrix within 10% of the samemechanical property for the same type of carbon black having a high PAH,can be with respect to at least one beneficial mechanical property, atleast two, at least three, at least four, at least five, at least six,at least seven, and/or all eight of these beneficial mechanicalproperties. In other words, the present invention has the ability toprovide a carbon black having a low PAH amount, such as a low PAH 22,and yet impart at least comparable mechanical properties or rubberproperties to a polymer matrix, such as an elastomer composition,wherein comparable is understood to mean within 10% (e.g., within 5% orwithin 1%) of the particular mechanical property.

For purposes of the present invention, a low PAH amount includes or isdefined by a low PAH 22. As indicated above, a PAR 22 is a measurementof PAHs as set forth in FIG. 1 of the present application. For purposesof the present invention, a low PAH amount can be defined by a low PAH22. Examples of suitable amounts include 500 ppm or less, 400 ppm orless, 300 ppm or less, 200 ppm or less, 150 ppm or less, 125 ppm orless, 100 ppm or less, 75 ppm or less, 50 ppm or less, 25 ppm or less,with respect to the amount of PAH 22 present in the carbon black.Suitable ranges include from about 1 ppm to about 500 ppm, 5 ppm to 500ppm, 15 ppm to 500 ppm, 5 ppm to 50 ppm, 5 ppm to 100 ppm, 1 ppm to 100ppm, or 1 ppm to 30 ppm, with respect to the total amount of PAH 22present in the carbon black. For any of the ranges or amounts providedabove, the lower limit can be 0.1 ppm, 1 ppm, 2 ppm, 5 ppm, 10 ppm, or15 ppm. The ranges can be exact or approximate (e.g., “about 1 ppm” andthe like). In at least one embodiment, these ppm ranges can apply to allor any number of PAHs (e.g., all PAHs or one or more of the PAHs). Forpurposes of the present invention, the PAH22 is a measurement of thePAHs identified in FIG. 1 except for Benzo(j)fluoranthrene. Also, thePAH8 for purposes of the present invention is a measurement ofBenzo(a)anthracene, Benzo(a)pyrene, Benzo(e)pyrene,Benzo(b)fluoranthrene, Benzo(j)fluoranthrene, Benzo(k)fluoranthrene,Chrysene, and Dibenzo(a,h)anthracene. BaP is a reference toBenzo(a)pyrene.

In one or more embodiments, one or more of the carbon black of thepresent invention can have a PAH content of from about 0.15 to about 2micrograms/m², such as from 0.2 to 1.5 micrograms/m², or from 0.3 to1.25 micrograms/m², or from 0.4 to 1.0 micrograms/m², and the like.

In one or more embodiments, and optionally as a separate embodiment, thepresent invention relates to a carbon black having a PAH content of fromabout 0.15 to about 2 micrograms/m² wherein said PAH content isdetermined based on a PAH22 content, and optionally the carbon black canhave any one or more of the characteristics and/or properties describedherein, and optionally can be part of a polymer or rubber formulation(or other formulation) as described herein. Other ranges include from0.2 to 1.5 micrograms/m², or from 0.3 to 1.25 micrograms/m², or from 0.4to 1.0 micrograms/m², and the like.

In one or more embodiments, the present invention relates to a carbonblack having a low PAH content. The PAH content can be determined and ispreferably determined based on a PAH22 content as shown herein. Thecarbon black can be a furnace carbon black or other carbon blackdescribed herein. In one or more embodiments, the carbon black havingthe low PAH content is based upon a particular STSA range, a particularI₂No/STSA ratio, as well as a particular PAM content and, in some cases,a particular DBP range. In one or more embodiments, the carbon black ofthe present invention can be selected from one or more of the followinggroups:

a) STSA: 110-250 m²/g

-   -   I₂No (mg/g)/STSA (m²/g). 1.2 to 0.70    -   PAH: 400 ppm or less

b) STSA: 80-110 m²/g

-   -   I₂No (mg/g)/STSA (m²/g): 1.15 to 0.70    -   PAH: 30 ppm or less

c) STSA: 65-75 m²/g

-   -   I₂No (mg/g)/STSA (m²/g): 1.10 to 0.88    -   PAH: 500 ppm or less;    -   DBP: 115-125 mL/100 g

d) STSA: 65-80 m²/g

-   -   I₂No (mg/g)/STSA (m²/g): 0.70 to 0.88    -   PAH: 500 ppm or less

e) STSA: 1 to 35 m²/g

-   -   I₂No (mg/g)/STSA (m²/g): 1.40 to 0.70    -   PAH: 50 ppm or less; or

f) STSA: 70 to 90 m²/g

-   -   I₂No (mg/g)/STSA (m/g): 1.00 to 1.20    -   PAH: 50 ppm or less    -   DBP: 60-80 mL/100 g; or

g) STSA: 87-95 m²/g

-   -   I₂No (mg/g)/STSA (m²/g): 0.91 to 1.08    -   PAH: 100 ppm or less    -   DBP: 109-119 mL/100 g.

The above groups provide a particular combination of properties and PAMcontent, which are especially useful in a variety of applicationsincluding, but not limited to, rubber or elastomer formulations (orother formulations) and the like.

With respect to each of the groups a) through g) above, the followingare examples of particular ranges, sub-ranges, and the like which can beused.

a) STSA (m²/g): 110-200; 110-180; 110-175; 110-130; 115-250; 115-200;115-180; 115-175; 120-250; 120-200; 120-175; 125-250; and/or

-   -   I₂No (mg/g)/STSA (m²/g): 1.15-0.7; 1.2-0.7; 1.1-0.7; 1.0-0.7;        0.9-0.7; 1.0-0.8; 1.2-0.8; 1.2-0.9; 1.15-0.8; and/or    -   PAH (ppm): 350 or less; 300 or less; 250 or less; 200 or less;        50 or less; 1-150; 100 or less; 20 or less; 1-200; 5-200;        10-200; 10-100; 5-150; 5-100; 5-50; 1-50; 1-20; 1-10.

b) STSA (m²/g): 80-105; 80-100; 80-90; 82-110; 83-110; 83-105; 85-105;90-110; 90-107; 83-100; and/or

-   -   I₂No (mg/g)/STSA (m²/g): 1.10 or less; 1.15-0.7; 1.15-0.8;        1.10-0.75; 1.0-0.75; 1.15-0.85; and/or    -   PAH (ppm): 1-20; 10 or less; 1-10; 5-30; 1-30; 3-30; 1-15; 1-25.

c) STSA (m²/g): 66-68; 67-75; 70-75; 68-72; 69-70; 70-74; and/or

-   -   I₂No (mg/g)/STSA (m²/g): 1.1-0.89; 1.1-0.90; 1.1-0.90; 1.0-0.96;        1.0-0.95; 1.05-0.90; and/or    -   PAH (ppm): 1-450; 400 or less; 350 or less; 300 or less, 250 or        less; 200 or less; 175 or less; 150 or less; 125 or less; 100 or        less; 75 or less; 55 or less, 45 or less; 1-5; 1-9; 1-8; 1-7;        1-6; 8 or less; 0.5-9.        An example of a carbon black of c) can be N-351 carbon black.

d) STSA (m²/g): 68-80; 70-80; 72-80; 70-77; 68-75; 72-80; 69-74; and/or

-   -   I₂No (mg/g)/STSA (m²/g): 0.88-0.72; 0.85-0.72; 0.83-0.70;        0.85-0.7; 0.85-0.75; and/or    -   PAH (ppm); 400 or less; 200 or less; 150 or less; 1-100; 50 or        less; 20 or less; 1-500; 1-400; 1-300; 1-200; 0.5-100; 0.5-50;        1-30; 1-25; 1-20; 1-10; 0.5-10; 0.5-5.

e) STSA (m²/g): 1-30; 3-25; 5-20; 7-20; 7-30; 2-20; 2-15; and/or

-   -   I₂No (mg/g)/STSA (m²/g): 1.3 or less; 1.2 or less; 1.15 or less;        1.10 or less; 1.0 or less; 0.9 or less; 1.4-0.7; 1.3-0.7;        1.25-0.7; 1.2-0.7; 1.15-0.7; 0.9-0.7; 0.95-0.7; 0.75-0.7; and/or    -   PAH (ppm): 1-20; 20 or less; 1-50; 1-40; 1-30; 1-20; 1-10;        0.5-5; 3-50; 3-25.

f) STSA (m²/g): 70-87; 70-85; 73-90; 73-85; 73-80; 72-77; and/or

-   -   I₂No (mg/g)/STSA (m²/g): 1.0-1.15; 1-1.1; 1.05-1.2; 1.05-1.15;        and/or    -   PAH (ppm): 20 or less; 10 or less; 1-20; 1-50; 1-40; 1-30; 1-20;        1-10; 0.5-5; 3-50; 3-25; and/or    -   DBP (mL/100 g): 65-80; 70-80; 72-80; 65-78; 68-77; 69-76.

An example of a carbon black of f) can be N-326 carbon black.

g) STSA (m²/g): 90-95; 89-94; 90-94; and/or

-   -   I₂No (mg/g)/STSA (m²/g): 0.92-1.07; 0.94-1.05; 0.96-1.03;        0.97-1.00; and/or    -   PAH (ppm). 80 or less; 60 or less; 50 or less; 40 or less; 30 or        less; 20 or less; 10 or less; 1-20; 1-50; 1-40; 1-30; 1-20;        1-10; 0.5-5; 3-50; 3-25; and/or    -   DBP (mL/100 g): 110-115; 112-114; 111-118; 113-117.

An example of a carbon black of g) can be N-375 carbon black.

Optionally, in addition to the PAH22 content or separately, the PAH8 forcarbon black a) can be 15 ppm or less (e.g., 12 ppm or less, 0.5 ppm to10 ppm, 1 ppm to 5 ppm, 5 ppm or less). In addition or in thealternative, the BaP can be 4 ppm or less (0.1 ppm to 4 ppm, 0.5 ppm to3 ppm). The carbon blacks of the present invention can have an equallylower PAH8 and in general can have a PAH8 that is at least 50% less(e.g., 50% to 80% lower) than the PAH 22 values described herein.Further, the BaP for the carbon blacks can be typically at least 75%lower (e.g., 75% to 95% lower) than the PAH22 values described herein.

In at least one embodiment of the present invention, the carbon black ofthe present invention can be a rubber grade or tire grade carbon blackas that term is understood in the industry. The carbon black of thepresent invention, in at least one embodiment, can have a STSA (m²/g) ofabout 20 m²/g to 200 m²/g or from about 20 m²/g to 150 m²/g or fromabout 80 to about 140 m²/g. For instance, STSA can be from about 80 toabout 100 m²/g or from about 80 to about 90 m²/g. As an option, thecarbon black can have an Iodine No./STSA ratio of less than 1.0, such as0.7 (or less) to 0.98.

In one or more embodiments, the carbon black of the present inventioncan have an I₂No./STSA ratio that is equal to or less than y, whereiny=0.004x+(0.6221)where y=I₂No./STSA and x=STSA, wherein STSA can be 20 m²/g to 150 m²/g.Iodine number (I₂ No.) of the carbon blacks is determined according toASTM Test Procedure D1510. STSA (statistical thickness surface area) isdetermined based on ASTM Test Procedure D-5816 (measured by nitrogenadsorption).

In at least one embodiment of the present invention, the carbon black,such as the rubber grade or tire grade carbon black, can have one ormore of the following mechanical properties or rubber properties incombination with the STSA of from 20 m²/g to 150 m²/g or from 80 toabout 140 m²/g, wherein the mechanical properties and/or rubberproperties are determined when the carbon black in present in a rubberformulation according to ASTM D 3191-02 Standard Test Methods for CarbonBlack in SBR—Recipe and Evaluation Procedures:

-   -   abrasion resistance (21% slip) of from 80 to 170;    -   elongation (%) of from 300 to 600;    -   tensile strength (Mpa) of from 20 to 35;    -   100% modulus (Mpa) of from 2.4 to 4.5;    -   300% modulus (Mpa) of from 12 to 23;    -   ratio of 300% modulus/100% modulus (M300%/1100%) of from 3.5 to        6;    -   bound rubber (%) of from 15 to 30; and/or    -   max tan delta@0° C. of from 0.25 to 0.4.

These properties can be achieved for one or more rubber compounds, andcan be achieved when the rubber is natural rubber and/or SBR.

In one or more embodiments of the present invention, the presentinvention relates to a carbon black having a low PAH amount as describedabove, as well as a STSA of from 20 m²/g to 150 m²/g or from 80 to 140m²/and having one or more of the following mechanical properties basedon the formula provided for each property, wherein x is the STSA (m²/g)of the carbon black and y is the mechanical property.

-   -   abrasion resistance (21% slip): y=5/6(x)+(43+/−10).

The other mechanical properties identified above can have the same orsimilar relationships with the STSA.

In one or more embodiments, the present invention relates to anelastomeric composition or rubber matrix containing a least one carbonblack of the present invention and at least one elastomer. The carbonblack can be used in the same proportions with respect to the elastomerthat are commonly used for carbon blacks having similar morphology buthigher levels of PAH. One of skill in the art will recognize that theappropriate proportion will depend upon the morphology of the carbonblack, the matrix composition, and the desired use of the filledpolymer. Depending on the surface area and structure, various carbonblacks may be employed at a loading of from about 10 phr to about 100phr, for example, about 10 phr to about 60 phr.

Furthermore, there is no criticality as to the elastomers used in thepresent invention to form the elastomeric composition. One or moreelastomers can be present, and the elastomers that can be used areconventional in the formation of elastomeric compositions, such asrubber compositions. The elastomer can be used in conventional amounts.

Any suitable elastomer may be compounded with the carbon blacks toprovide the elastomeric compounds of the present invention. Suchelastomers include, but are not limited to, homo- or co-polymers of 1,3butadiene, styrene, isoprene, isobutylene, 2,3-dimethyl-1,3-butadiene,acrylonitrile, ethylene, and propylene The elastomer can have a glasstransition temperature (Tg) as measured by differential scanningcolorimetry (DSC) ranging from about −120° C. to about 0° C. Examplesinclude, but are not limited, styrene-butadiene rubber (SBR), naturalrubber, polybutadiene, polyisoprene, and their oil-extended derivatives.Blends of any of the foregoing may also be used.

Among the rubbers suitable for use with the present invention arenatural rubber and its derivatives such as chlorinated rubber. Thecarbon blacks of the invention may also be used with synthetic rubberssuch as: copolymers of from about 10 to about 70 percent by weight ofstyrene and from about 90 to about 30 percent by weight of butadienesuch as copolymer of 19 parts styrene and 81 parts butadiene, acopolymer of 30 parts styrene and 70 parts butadiene, a copolymer of 43parts styrene and 57 parts butadiene and a copolymer of 50 parts styreneand 50 parts butadiene; polymers and copolymers of conjugated dienessuch as polybutadiene, polyisoprene, polychloroprene, and the like, andcopolymers of such conjugated dienes with an ethylenic group-containingmonomer copolymerizable therewith such as styrene, methyl styrene,chlorostyrene, acrylonitrile, 2-vinyl-pyridine, 5-methyl2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine,alkyl-substituted acrylates, vinyl ketone, methyl isopropenyl ketone,methyl vinyl either, alphamethylene carboxylic acids and the esters andamides thereof such as acrylic acid and dialkylacrylic acid amide; alsosuitable for use herein are copolymers of ethylene and other high alphaolefins such as propylene, butene-1 and pentene-1.

The elastomeric compounds of the present invention may be additionallycompounded with one or more coupling agents to further enhance theproperties of the elastomeric compound. Coupling agents, as used herein,include, but are not limited to, compounds that are capable of couplingfilters such as carbon black or silica to an elastomer. Useful couplingagents include, but are not limited to, silane coupling agents such asbis(3-triethoxysilylpropyl)tetrasulfane (Si-69),3-thiocyanatopropyl-triethoxy silane (Si-264, from Degussa AG, Germany),γ-mercaptopropyl-trimethoxy silane (A189, from Union Carbide Corp.,Danbury, Conn.); zirconate coupling agents, such as zirconiumdineoalkanolatodi(3-mercapto) propionato-O (NZ 66A, from KenrichPetrochemicals, Inc., of Bayonne, N.J.); titanate coupling agents; nitrocoupling agents such asN,N′-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane (Sumifine 1162, fromSumitomo Chemical Co., Japan); and mixtures of any of the foregoing. Thecoupling agents may be provided as a mixture with a suitable carrier,for example X50-S which is a mixture of Si-69 and N330 carbon black,available from Degussa AG.

Elastomeric compositions disclosed in the present invention include, butare not limited to, vulcanized compositions (VR), thermoplasticvulcanizates (TPV), thermoplastic elastomers (TPE) and thermoplasticpolyolefins (TPO). TPV, TPE, and TPO materials are further classified bytheir ability to be extruded and molded several times without loss ofperformance characteristics.

The elastomeric compositions of the present invention can thereforecontain an elastomer, curing agents, reinforcing filler, a couplingagent, and, optionally, various processing aids, oil extenders, andantidegradents. In addition to the examples mentioned above, theelastomer can be, but is not limited to, polymers (e.g., homopolymers,copolymers, and terpolymers) manufactured from 1,3 butadiene, styrene,isoprene, isobutylene, 2,3-dimethyl-1,3 butadiene, acrylonitrile,ethylene, propylene, and the like. It is preferred that these elastomershave a glass transition point (Tg), as measured by DSC, between −120° C.and 0° C. Examples of such elastomers include poly(butadiene),poly(styrene-co-butadiene), and poly(isoprene).

The elastomeric compositions may include one or more curing agents suchas, for example, sulfur, sulfur donors, activators, accelerators,peroxides, and other systems used to effect vulcanization of theelastomer composition. The following patents provide examples of variousingredients, such as curing agents, elastomers, uses, and the like whichcan be used in the present invention: U.S. Pat. Nos. 6,573,324;6,559,209; 6,518,350; 6,506,849; 6,489,389; 6,476,154; 6,878,768;6,837,288; 6,815,473; 6,780,915; 6,767,945; 7,084,228; 7,019,063; and6,984,689. Each of these patents is incorporated in their entirety byreference herein.

The compositions (e.g., elastomeric or other compositions orformulations) of the present invention can contain, as an option, carbonblacks having a high PAH or can contain any conventional carbon blacks(or any other fillers or reinforcing agents), along with the carbonblacks of the present invention. Preferably, the amounts of the higherPAH carbon blacks or conventional carbon blacks is zero to minoramounts, such as 30% by weight or less of the total carbon black present(e.g., 0 wt % to 30 wt %, or 0.01 wt % to 10 wt %, or 0.01 wt % to 1 wt%).

Conventional techniques that are well known to those skilled in the artcan be used to prepare the elastomeric compositions and to incorporatethe carbon black. The mixing of the rubber or elastomer compound can beaccomplished by methods known to those having skill in the rubber mixingart. For example, the ingredients are typically mixed in at least twostages, namely at least one non-productive stage followed by aproductive mix stage. The final curatives are typically mixed in thefinal stage which is conventionally called the “productive” mix stage inwhich the mixing typically occurs at a temperature, or ultimatetemperature, lower than the mix temperature(s) of the precedingnon-productive mix stage(s). The terms “non-productive” and “productive”mix stages are well known to those having skill in the rubber mixingart. Wet masterbatch methods for producing filled elastomericcompositions, such as those disclosed in U.S. Pat. Nos. 5,763,388,6,048,923, 6,841,606, 6,646,028, 6,929,783, 7,101,922, and 7,105,595 mayalso be employed to produce elastomeric compositions containing carbonblacks according to various embodiments of the invention, and thesepatents are incorporated in their entirety by reference herein.

With respect to the elastomeric compositions or rubber matrices of thepresent invention, the elastomeric composition contains at least onecarbon black of the present invention and at least one elastomer. Theelastomeric composition can have one or more of thepreviously-identified mechanical properties in any of the embodimentsidentified above. Various articles of manufacture, including tires andindustrial products, may contain at least one component comprised of anelastomeric composition of this invention. For example, the elastomericcomposition of this invention may be used in forming a composite withreinforcing material such as in the manufacture of tires, belts orhoses. Preferably, the composition of the present invention is in theform of a tire and more specially as a component of a tire, including,for example, one or more of the tire's tread, wirecoat, beadcoat,sidewall, apex, chafer and plycoat.

The carbon blacks of the present invention can be made a variety ofways, For instance, one can start with a carbon black that iscommercially available. Examples of starting materials include, but arenot limited to, commercially available rubber grade carbon black or tiregrade carbon blacks, which include N234 carbon blacks. The carbon blackcan be a N100 series, N200 series, N300 series, N400 series, N500series, N600 series, and/or N700 series of carbon black. For instance,carbon blacks that can be used include, but are not limited to, N110 toN990 ASTM carbon blacks (e.g., N110, N121, N220, N231, N234, N299, N326,N330, N339, N347, N351, N358, N375, N539, N550, N650, N660, N683, N762,N765, N774, and/or N990). The carbon black can be a N220 to N375 ASTMcarbon black. Commercially available examples of starting materialsinclude, but are not limited to, Vulcan® 7H carbon black and Vulcan® Jcarbon black from Cabot Corporation. The commercially available carbonblacks can then be treated to remove at least a portion of the PAH withthe carbon black, which is generally on the surface of the carbon black.Generally, the amount of PAH removed, and more preferably the PAH 22removed, is an amount sufficient to achieve the low PAH valuesidentified above.

The carbon blacks of the present invention can be prepared with respectto the STSA parameter and the I₂No/STSA from commercially availabletechniques which are used to form, for instance, Vulcan® grade carbonblacks, Sterling® grade carbon blacks, Regal® carbon blacks, BlackPearl® carbon blacks, ASTM grade carbon blacks, rubber grade carbonblacks, Spheron® carbon blacks, and the like. Specific examples include,but are not limited to, ASTM 121 carbon black, Vulcan® 10 carbon black,Vulcan® 10H carbon black, Vulcan® M carbon black, Vulcan® J carbonblack, Regal® 300 carbon black, Vulcan® 3 carbon black, Vulcan® 3Hcarbon black, Vulcan® K carbon black, Sterling® SO carbon black,Sterling® NS1 carbon black, Regal® 85 carbon black, Spheron® 5000 carbonblack, and the like. While the techniques used to commercially makevarious carbon blacks having the STSA and/or I₂No/STSA ratio can beused, the techniques explained herein with respect to achieving, at thesame time, the desirable low PAH range are to be used in combination inorder to produce a combination of suitable parameters, which are usefulin a variety of applications, including rubber and elastomerformulations, and other formulations and applications.

An example of a process to remove the PAH can include subjecting ortreating the carbon black having the higher PAH to/with sufficient heat,optionally in an inert (e.g., nitrogen) or vacuum atmosphere, such thatthe PAH or a portion thereof is removed. The carbon black can be, forinstance, subjected to a sufficient temperature on the order of fromabout 300° C. to about 500° C. (or higher, such as 500° C. to 950° C.)to remove a substantial portion of the PAH from the carbon black toachieve the desirable low PAH values provided above. The heating canoccur for any time sufficient to achieve the removal of the PAH, such asfrom about 10 minutes to about 10 hours or more. The heating can occurin any type of furnace or other device capable of subjectingparticulates to heat and preferably in an inert or vacuum atmosphere.The temperature with regard to the heat treatment is with respect to thetemperature that the carbon black achieves and this temperature can befrom 300° C. to 500° C., such as 350° C. to 500° C., or 400° C. to 500°C., and the like. Temperatures above 500° C. can be used, such as 500°C. to 750° C. or from 500° C. to 950° C. or higher.

In another process, the PAH can be removed or reduced from the carbonblack by subjecting the carbon black to a solvent extraction process,such as a Soxhlet extraction using an organic solvent, such as toluene.Other examples of suitable solvents that can be used include, but arenot limited to, acetone, hexane, cyclohexane, methylene chloride,xylene, dimethyl sulphoxide, tetrahydrofuran, or any mixtures of these.Generally, any amount of the solvent can be used. For instance, for 100grams of carbon black, 250 mls to 1 liter (or more) of solvent can beused, and amounts below or above these ranges can be used. Theextraction can be an hour or more, such as for 24 hours or more,especially with respect to a Soxhlet extraction. A carbon black can besubjected to multiple treatments (e.g., heat and solvent extraction,multiple heat treatments, and/or multiple solvent extractions with thesame or different solvents).

With respect to forming carbon black with low PAH amounts, this processcan be conducted right after the carbon black is formed or can be usedwith carbon black previously made. Thus, the processes of the presentinvention can be incorporated into a continuous process to make carbonblack. In addition, in the present application, carbon blacks can beformed having a low PAH amount during the manufacturing of carbon black,for instance, wherein the hot tail gas from a carbon black manufacturingprocess is removed so that the PAHs do not condense on the carbon blackduring the manufacturing process. The carbon black that can be formed bythis process can be any carbon black previously described earlier orother grades. The carbon black can be separated from the gas phase at atemperature of from about 260° C. to about 950° C., such as about 750°C. or about 800° C., such that the PAH in gas form can be easilyremoved, and this temperature is low enough that it does not affect thesurface of the carbon black. Other temperature ranges include from 300°C. to 900° C., from 400° C. to 900° C., from 500° C. to 900° C., from600° C. to 900° C., from 650° C. to 900° C., from 700° C. to 850° C.,and the like or approximations thereof. Any carbon black, such as anyASTM grade carbon black, can be made in this manner and achieve a lowPAH amount.

For example, it is believed that heat treatment, such as in inertatmosphere, allows the PAH compounds to be volatilized and subsequentlydesorbed from the surface of carbon black leaving the other surfacechemistry unaffected. FIG. 2 shows the reduction in PAH 22 for V7H as afunction of heat treatment temperature in nitrogen atmosphere. The graphshows that as treatment temperature is increased, total PAH levels arereduced, and at a temperature of about 500° C. almost 75 wt % of thePAHs were removed. In the reactor, the PAH molecules, synthesized by thepyrolytic process exist in the gas phase, and as the black is cooled totemperatures below 200° C., a majority of the PAHs condense on thesurface of carbon black. Due to the hysteresis between desorption andadsorption curves, it is possible to remove equal amounts of PAH at muchlower temperature on the adsorption curve, than on the desorption curve.Thus, carbon black can be separated from tail gas at high temperatures,while the PAHs are still in gas phase, and the process will produce lowPAH amount carbon blacks.

Thus, in one or more embodiments, the present invention relates to theproduction of a carbon black of the present invention, wherein themethod comprises subjecting or treating a carbon black having a PAHabove 500 ppm to/with sufficient heat, optionally in an inert or vacuumatmosphere, such that the PAH or a portion thereof is removed to formsaid carbon black. The heat can be on the order of from about 300° C. toabout 950° C., wherein the heat is the temperature that the carbon blackwill reach.

In one or more embodiments, the carbon black of the present inventioncan be formed during the manufacturing of carbon black, which involvesthe presence of hot tailgas containing a carbon black and PAH. Themethod comprises removing the hot tailgas that contains the PAH in anymanner from the carbon black. The hot tailgas can be at a temperature offrom 260° C. to about 950° C., such as 400° C. to about 900° C., or fromabout 500° C. to about 950° C., while the hot tailgas is being removedfrom the carbon black. The manufacturing of the carbon black in thisprocess can occur in a conventional furnace carbon black reactor using aconventional process, such as described in U.S. Pat. Nos. 6,926,877;6,485,693; 6,273,142; 6,024,135; 6,348,181; 6,156,837; 6,086,841; and5,190,739, with the differences or changes noted herein. In one or moreembodiments, a cyclone or cyclone filter is used to separate the hottailgas from the carbon black, so that the carbon black can be recoveredwithout high PAH contents. In the alternative, or in combination, a hightemperature filter can be used as described above. In the process, theprocess can include lowering or reducing the carbon black temperature,once removed from the tailgas, to a temperature below 400° C. or below200° C. prior to introducing the recovered carbon black into a bagfilter or other storing container. Any manner to lower the carbon blacktemperature to below 200° C. or to below 400° C. can be used, such as acool inert gas, or other cooling mechanisms, such as a cooling jacket,and the like. For instance, a steam fluidized bed can be used. Theseparation of the hot tailgas from the carbon black can occur at anypoint once the hot tailgas is no longer needed for purposes of formingthe carbon black at the desired specifications. The hot tailgas can beremoved generally prior to the quench and after carbon black formationin the tailgas. With the present invention, and unlike previousconventional carbon black manufacturing processes, the hot tailgas isnot cooled down to lower the tailgas temperature, but instead, the hottailgas is removed from the carbon black. By doing so, the hot tailgascan then be recycled for any use. For instance, the hot tailgas can berecycled to the same or different carbon black furnace reactor, forinstance, using the system described in WO 2000/032701, incorporated inits entirety by reference herein, wherein the dewatering step can beskipped. Also, or as an alternative, the hot tailgas can be recycled bybeing used as a heat source for any energy needs. In the alternative, orin addition, the recycled hot tailgas can be directed to one or moredryers, such as carbon black dryers, and serve as a heat source orpartial heat source to the dryer. For instance, carbon black dryers areused to dry carbon black and, therefore, require a substantial heatsource to generate a high enough temperature to remove the moisture fromthe carbon black. The recycled hot tailgas can be directed to the dryerand serve as at least a partial heat source to the dryer. It is notedthat by being at least a part of the heat source to the dryer,temperatures can be sufficiently reached such that the PAH in thetailgas is partially or totally destroyed. In other words, the PAH inthe tailgas will be broken down into non-PAH molecules or otherwiseconsidered no longer a PAH. Thus, not only does this recycling provide ause for the hot tailgas, it further leads to a beneficial breakdown ofthe PAH such that it no longer poses a risk as a PAH.

For purposes of the present invention, a short quench carbon black is acarbon black formed by a process wherein the carbon black, afterformation from pyrolysis, is subjected a short quench to stop the carbonblack forming reactions. The short quench is a parameter of the furnacecarbon black manufacturing process that assures the value of the CBToluene Discoloration (tested per ASTM D1618) of 95%, or lower. In theprocess of the present invention, the process of removing the PAH fromthe carbon black is especially useful where the carbon black is formedin a furnace (e.g., furnace-type blacks) and are especially effectivewhere the carbon blacks are formed from the use of a short quench, asthat term is understood. Examples of short quench carbon blacks include,but are not limited to, Vulcan® 7H carbon black, Vulcan® J carbon black,Vulcan® 10H carbon black, Vulcan® 10 carbon black, Vulcan® K carbonblack, Vulcan® M carbon black, and N-121 carbon black. In one or moreembodiments, the present invention thus relates to a short quench carbonblack having a PAH content of 100 ppm or less. The short quench carbonblack can be a furnace carbon black. The PAH content is determined basedon a PAH22 content. The short quench carbon black can be a N110 to N787ASTM carbon black. The short quench carbon black can have any of theparameters described above with respect to PAH content, STSA, I₂No(mg/g)/STSA (m²/g) ratio, DBP, and the like.

Furthermore, in the present invention, the present invention canselectively remove certain types of PAHs from the carbon black. Forinstance, low molecular weight PAHs on the order of less than 200 (e.g.,1 to 199) can be substantially removed by the processes of the presentinvention. The low MW PAHs can have the ppm levels referenced above forthe PAH 22. Also, the type of processes can selectively remove PAHs or agreater percent of them. For instance, heating can remove the followingPAHs in a greater percent: coronene, fluoranthene, acenaphthylene,cyclopenta(cd)pyrene, anthanthrene, or indenopyrene. Solvent extractioncan remove the following PAHs in a greater percent: pyrene, naphthalene,benzo(e)pyrene, benzo(ghi)fluoranthene, or 1,12 benzperylene.

The carbon black of this invention may be used in the same applicationsas conventional carbon blacks. More than one type of carbon black of thepresent invention can be used in any formulation, composition, orapplication.

Carbon black according to the invention can be used in a number of enduse applications. These uses include, for example, plastic compositions,inks, toners, printing plates, coatings, rubber compositions, papercompositions, moldings, molding compositions, films, pipes, and textilecompositions.

The carbon black of this invention may be used as pigments or colorantsin any matrix, such as in a plastic material. The carbon black of theinvention can also be used to impart conductivity to a plastic material.

The carbon black can be used with a variety of plastics, including butnot limited to plastics made from thermoplastic resins, thermosettingresins, or engineered materials, for example, composites. Typical kindsof thermoplastic resins include: (1) acrylonitrile-butadiene-styrene(ABS) resins; (2) acetals; (3) acrylics; (4) cellulosics; (5)chlorinated polyethers; (6) fluorocarbons, such aspolytetrafluoroethylene (TFE), polychlorotrifluoroethylene (CTFE), andfluorinated ethylene propylene (FEP); (7) nylons (polyamides); (8)polycarbonates; (9) polyethylenes (including copolymers); (10)polypropylenes (including copolymers); (11) polystyrenes; (12) vinyls(polyvinyl chloride); (13) thermoplastic polyesters, such aspolyethylene terephthalate or polybutylene terephthalate; (14)polyphenylene ether alloys; and blends and alloys of the above withrubber modifiers. Typical thermosetting resins include: (1) alkyds; (2)allylics; (3) amino (melamine and urea); (4) epoxies; (5) phenolics; (6)polyesters; (7) silicones; and (8) urethanes.

Generally, the carbon black product is added like any other pigment tothe plastic used to form a plastic premix. This can be done, forexample, in a dry mix or a melt stage. The carbon black of the inventionmay be used in combination with other conventional additives in plasticcompositions. According to the invention, the term plastic compositionincludes, but is not limited to, any plastic material, article, goods,surface, fabric, sheet, and the like. For example, plastic materialsinclude automotive parts, siding for homes, liners for swimming pools,roofing materials, packaging materials, and any variety of otherhousehold or industrial items.

The carbon black of this invention is also useful in ink formulations.Other ink additives may be incorporated into the ink formulation.

In general, an ink consists of four basic components: (1) a colorant orpigment, (2) a vehicle or varnish which functions as a carrier duringprinting, (3) additives to improve printability drying, and the like,and (4) solvents to adjust viscosity, drying and the compatibility ofthe other ink components. For a general discussion on the properties,preparation and uses of aqueous inks, see The Printing Manual, 5th Ed.,Leach et al, Eds. (Chapman and Hall, 1993). Various aqueous inkcompositions are also disclosed, for example, in U.S. Pat. Nos.2,833,736, 3,607,813, 4,104,833, 4,308,061, 4,770,706, and 5,026,755. Ananother example, flexographic inks represent a group of inkcompositions. Flexographic inks generally include a colorant, a binder,and a solvent.

The carbon black of the invention, either as predispersion or as asolid, can be incorporated into an ink formulation using standardtechniques.

The carbon black of the invention can be used in news inks. For example,an aqueous news ink composition may comprise water, the carbon black ofthe invention, a resin and conventional additives such as antifoamadditives or a surfactant.

The carbon black of the invention may also be used in coatingcompositions such as paints or finishes. Other known aqueous coatingadditives may be incorporated the coating compositions. See, forexample, MCGRAW-HILL ENCYCLOPEDIA OF SCIENCE & TECHNOLOGY, 5^(th) Ed.(McGraw-Hill, 1982). See also U.S. Pat. Nos. 5,051,464; 5,319,044;5,204,404; 5,051,464; 4,692,481; 5,356,973; 5,314,945; 5,266,406; and5,266,361.

The carbon black of the invention may also be used in papercompositions. Accordingly, the invention relates to an improved paperproduct comprising paper pulp and a carbon black.

The paper products of the invention may incorporate other known paperadditives such as sizing agents, retention aids, fixatives, fillers,defoamers, deflocculating agents, and the like.

The carbon black of the invention may also be used, as with conventionalcarbon blacks, as pigments, fillers, and reinforcing agents in thecompounding and preparation of rubber compositions.

Carbon blacks of the present invention, for example, are useful in thepreparation of rubber vulcanizates such as those in tires. It isgenerally desirable in the production of tires to utilize carbon blackswhich produce tires with satisfactory abrasion resistance and hysteresisperformance. The treadwear properties of a tire are related to abrasionresistance. The greater the abrasion resistance, the greater the numberof miles the tire will last without wearing out. The hysteresis of arubber compound means the difference between the energy applied todeform a rubber compound, and the energy released as the rubber compoundrecovers to its initial undeformed state. Tires with lower hysteresisvalues reduce rolling resistance and therefore are able to reduce thefuel consumption of the vehicle utilizing the tire. Thus, it isparticularly desirable to have carbon black capable of imparting greaterabrasion resistance and lower hysteresis in tires.

The carbon black of this invention may also be used to color fibers ortextiles. Fibers suitable for use comprise natural and synthetic fiberssuch as cotton, wool, silk, linen, polyester and nylon. Textilessuitable for use comprise natural and synthetic fibers such as cotton,wool, silk, linen, polyester and nylon. Preferably natural fibers andtextiles comprising cotton, wool, silk and linen are used.

The carbon black of the present invention can be used to color fibersand textiles with, for example, direct and acid dyes. For a generaldiscussion of coloring with dyes, see KIRK-OTHMER ENCYCLOPEDIA OFCHEMICAL TECHNOLOGY, Vol. 8, pp. 280-350, “Dyes, Application andEvaluation” (John Wiley and Sons, 1979).

With respect to toners or toner resins, suitable toner resins for use inthe toner and developer compositions of the present invention include astyrenic polymer-based, such as a styrenated acrylic resin. Examples ofpreferred styrenic polymer-based resins include, but are not limited to,homopolymers and copolymers of styrene and its derivatives such as:polystyrene; poly-p-cholorostyrene; polyvinyltoluene;styrene-p-chlorostyrene copolymer; and styrene-vinyltoluene copolymer;copolymers of styrene and acrylic acid esters such as:styrenemethylacrylate copolymer; styrene-ethylacrylate copolymer; andstyrene-n-butyl acrylate copolymer; copolymers of styrene andmethacrylic acid esters such as: styrene-methyl methacrylate copolymer;styrene-ethyl methacrylate copolymer; styrene-n-butyl methacrylatecopolymer; and multi-component copolymers of styrene, acrylic acid esterand methacrylic acid esters; copolymers of styrene and other vinylmonomers such as: styrene-acrylonitrile copolymer, styrene-methyl ethercopolymer; styrene-butadienee copolymer; styrene-vinyl methyl ketonecopolymer; styrene-acrylonitrileindene copolymer; styrene maleic acidester copolymer; and the like. These binder resins may be used singly orin combination. Generally, resins particularly suitable for use inxerographic toner manufacturing have a melting point (ring and ballmethod) in the range of 100° C. to 135° C. and have a glass transitiontemperature (Tg) greater than about 60° C. Examples of styrenicpolymer-based resin particles and suitable amounts can also be found inU.S. Pat. Nos. 5,278,018; 5,510,221; 5,275,900; 5,571,654; 5,484,575;and EP 0 720 066 A1, all incorporated in their entirety by referenceherein.

Generally, the carbon black of the present invention, alone or withother pigments, is present in total amounts of from about 1% by weightto about 30% by weight of the toner or developer composition. The amountof pigment present in the toner composition is preferably from about 0.1to about 12 wt parts per 100 wt parts of resin, However, lesser orgreater amounts of the carbon black may be used. Also, generally, thetoner resin is present in amounts of from about 60% by weight to about99% by weight of the toner or developer composition.

Optional external additives may also be mixed or blended with the tonercompositions of the present invention including carrier additives;additional positive or negative charge controlling agents such asquaternary ammonium salts, pyridinum salts, sulfates, phosphates, andcarboxylates; flow aid additives, silicone oils; waxes such ascommercially available polypropylenes and polyethylenes; magnetite; andother known additives. Generally, these additives are present in amountsof from about 0.05% by weight to about 30% by weight, however, lesser orgreater amounts of the additives may be selected depending on theparticular system and desired properties. Specific examples of additivesand amounts are also described in the patents and the European patentapplication mentioned above and incorporated herein by reference.

The toner compositions can be prepared by a number of known methods,such as admixing and heating the resin, the carbon black particles,optional charge enhancing additives and other additives in conventionalmelt extrusion devices and related equipment. Other methods includespray drying and the like. Compounding of the carbon black and otheringredients with the resin is generally followed by mechanical attritionand classification to provide toner particles having a desired particlesize and particle size distribution. Conventional equipment for dryblending of powders may be used for mixing or blending the carbon blackparticles with the resin. Again, conventional methods of preparing tonerand developer compositions can be used and are described in the patentsand European application described above and incorporated herein byreference.

In more detail, the toner material can be prepared by dry blending thebinder resin with all other ingredients, including the pigment, and thenmelt-extruding in a high shear mixer to form a homogeneously mixed mass.During this process the components are held at a temperature above themelting point of the binder resin, and those components that areinsoluble in the resin are ground so that their average particle size isreduced. This homogeneously mixed mass is then allowed to cool andsolidify, after which it is pre-ground to an average particle size ofabout 100 microns. This material is then further subjected to particlesize reduction until its average particle size meets the size rangespecification required for classification. A variety of classifyingtechniques may be used. The preferred type is an air classificationtype. By this method, particles in the ground material which are toolarge or too small are segregated from the portion of the material whichis of the desired particle size range.

The toner composition of the present invention may be used alone inmonocomponent developers or may be mixed with suitable carrier particlesto form dual component developers. The carrier vehicles which can beused to form dual component developer compositions can be selected fromvarious materials. Such materials typically include carrier coreparticles and core particles overcoated with a thin layer offilm-forming resin to help establish the correct triboelectricrelationship and charge level with the toner employed. Suitable carriersfor two component toner compositions include iron powder, glass beads,crystals of inorganic salts, ferrite powder, nickel powder, all of whichare typically coated with resin coating such as an epoxy or fluorocarbonresin. Examples of carrier particles and coatings that can be used andare described in the patents and European application described aboveand incorporated herein by reference.

The present invention is further directed to a method of imaging whichincludes formulating an electrostatic latent image on a negativelycharged photoconductive imaging member, affecting the developmentthereof with toner composition comprising resin particles and carbonblack particles, and thereafter transferring the developed image onto asuitable substrate. Conventional methods of imaging can be used, such asshown in the patents and European patent application described above.

The carbon blacks of the present invention can also be used as acomponent in molding, films, or pipes. Conventional formulations can beused but wherein the carbon black of the present invention is presentinstead of conventional carbon black. Various articles containing thelow PAH amount carbon blacks of the present invention provides one orbenefits, including an article that contains less PAH.

The present invention will be further clarified by the followingexamples, which are intended to be exemplary of the present invention.

EXAMPLES Example 1

The carbon black samples that are included in the study are thematerials manufactured by Cabot Corporation with a furnace process (see,J. B. Donnet, R. C. Bansal, M. J. Wang, “Carbon Black,” SCIENCE ANDTECHNOLOGY, 2^(nd) Edition, Marcel Dekker, NY, 1993; and M. J. Wang, C.A. Gray, S. A. Reznek, K. Mahmud, Y. Kutsovsky, “Carbon Black,” inKIRK-OTHMER ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY, John Willey & Sons,2005, 4, 761). The properties of carbon black are defined by the ASTM(see, ASTM D 1765-03 Standard Classification System for Carbon BlacksUsed in Rubber Products) and by the Cabot specifications (see, Web sitewww.cabot-corp.com).

The carbon blacks were evaluated in the SBR rubber compound by the ASTM(see, ASTM D 3191-02 Standard Test Methods for Carbon Black inSBR—Recipe and Evaluation Procedures). Typical rubber mixing processesand tests are described in Maurice Morton, RUBBER TECHNOLOGY, 3rdEdition, Van Norstrand Reinhold Company, New York, 1987, and 2ndEdition, Van Norstrand Reinhold Company, New York, 1973). Testing ofbound rubber is described in G. Kraus, RUBBER CHEM TECHN, v 38, 1070(1965) and S. Wolff, M-J Wang, E-H Tan, RUBBER CHEM TECHN, v 66, 163(1993). Max Tan Delta is a measure of hysteresis (rolling resistance) ofrubber. It was tested using an ARES/Rheometrics Dynamic Spectrometer II(RDS II, Rheometrics, Inc., N.J.) operated in a torsion strain mode(shear). The measurements were performed at 0° C. for strain sweeps withdouble strain amplitude (DSA) ranging from 0.2 to 120%, at a constantfrequency of 10 Hz. Wear resistance was tested using the Cabot Abrader(see, U.S. Pat. No. 4,995,197).

Testing of PAH concentrations was conducted by the Cabot procedure thatincludes extraction by toluene with GCMS analysis for 22 individualPAHs, as identified in FIG. 1. The method is described in 21 C.F.R. part17B, FDA FEDERAL REGISTER, v62, #90. Friday, May 9, 1997.

Example 2

In the examples below, two commercially available carbon blacks fromCabot Corporation were tested, namely Vulcan® 7H carbon black andVulcan® J carbon black. The carbon blacks were subjected to twotechniques to remove PAH is, namely extraction by a Soxhlet extractionor the heating of the carbon black. In particular, the extraction andheating tests are set forth below.

Extraction of 100 gm samples of carbon black was conducted in Soxhletsfor 48 hours with 1500 ml of toluene.

Heating of the carbon black was conducted in an oven with circulation ofair or a nitrogen environment. A tray with the size of 1″×12″×12″ wasused to spread a 100 gm carbon black sample. Temperature of heatingvaried between 285 C and 500 C. Each heating condition was applied for 1hour period. Heating temperatures and environments are specified inTable 1 and 2 for each studied sample of carbon black.

The results of this testing are set forth below. As can be seen, theextraction by use of a solvent and the removal of PAHs by the use ofheat was effective to significantly reduce the PAH and, in particular,the PAH 22. More importantly, the mechanical properties achieved in theelastomer composition or rubber matrix were substantially maintainedirrespective of the PAH, which was quite surprising and important if lowPAH amount carbon black, especially rubber grades, are considered to beacceptable to the tire industry and rubber industry.

TABLE 1 CB ASTM Cabot BaP, PAH8, PAH22, Elongation, # Name TreatmentHeat Envirnmt ppm ppm ppm % N375 VJ none none Std 16 38 770 415 N234 V7Hnone none Std 12 34 860 420 N234 V7H Heat 285 Std 12 34 840 429 N234 V7HHeat 400 Std 6 18 380 429 N234 V7H Heat 500 Std 3 8.4 124 436 N234 V7HExtraction none Toluene 2.3 4.79 140 431 N375 VJ Extraction none Toluene1.2 2.59 52 431

TABLE 2 Abr Tensile 100% 300% Res, Bound strength, Modulus, Modulus, 21%Rubber, Max Tan ASTM # Mpa Mpa Mpa M300/M100 slip % Delta@0 C. N37527.69 3.6 19.03 5.29 134 19.02 0.352 N234 28.17 3.64 18.24 5.01 157 19.70.362 N234 28.54 3.68 18.83 5.12 162 19.28 0.358 N234 29.02 3.94 19.284.89 165 19.76 0.359 N234 29.35 3.64 19.09 5.24 158 20.74 0.357 N23426.76 3.22 17.05 5.3 143 19.83 0.361 N375 27.5 3.26 17.43 5.35 130 18.70.355

Example 3

This experiment was carried out for production of carbon blacks withvery low PAH content by hot gas separation. PAH molecules are reformedin the reactor at high temperatures and as the reactor stream is cooled,they condense on the surface of carbon black. The experiment employed acyclone to separate tail gas from carbon black at a temperature of about750° C., such that the PAH molecules remained in the gas phase and werenot allowed to condense on the carbon black. The carbon black was anSTSA equivalent of V7H (112 m²/g). During the collection of the samplethrough a cyclone by drawing a side-stream from the reactor, samplesfrom MUF (Main Unit Filter) and pelletizer were also collected ascontrols. The carbon black collected in the cyclone had a total PAHcontent of about ˜16 ppm, which turned out to be two orders of magnitudelower than the control samples collected as a part of standardmanufacturing procedure. A study of natural rubber compound propertiesshowed that the low PAH amount carbon black thus collected wasequivalent in performance to the control samples.

Hot gas separation of carbon black was performed in the pilot plantreactor using a cyclone (“cyclone” in the tables is a reference to thesesamples of the present invention) to reduce the condensation of PAH oncarbon black. The goal was to separate kilogram quantity of black, studythe PAH and also the compound properties along with the control samples(separated by regular process in the MUF). The experiment drew a sidestream from the carbon black reactor for the hot gas separation. In lieuof cyclone recovery of low PAH amount blacks, high temperaturefiltration could be used. For instance, ceramic filters (manufacturer:Caldo) or sintered metal filters (manufacturer: Applied PorousTechnologies) that can sustain the desired temperatures of separation(˜750° C.) can be used.

The place used for drawing a reactor sample for separation was betweenthe reactor quench and the heat exchanger, since the reactor temperaturedownstream of quench is of the order of 750° C. and that there would beseveral quench ports available for drawing the sample. The experimentinvolved separation of carbon black from tail gas while hot, andsecondly, cooling of carbon black to temperatures below ˜200° C. beforeexposure to air to preferably avoid oxidation of the surface. In theexperiment, a cyclone separation system was connected to one of thequench ports downstream of the reactor quench, the carbon black droppedinto a container attached to the bottom of the cyclone, while the leantail gas (stripped off of carbon black) was forced back into the reactordownstream using an eductor (quench aspirator, in this case) with 100psi steam line as the motive flow. Temperature of separation wasmeasured at different locations in the sampling system. The samplingsystem was connected to an off-line reactor section to determine if thesuction created by steam eductor was sufficient for the sampling systemto draw a stream out of the reactor.

The entire sampling system, mainly the sample container at the bottom ofthe cyclone, was pre-heated to avoid any condensation of PAH while thesystem was cold. Though optional, hot N₂ (@800° C.) was sparged throughtwo sintered metal porous tubes, placed diametrically opposite insidethe container. The same tubes were used for cooling the carbon blackafter collection by sparging cold N₂ through the tubes. Twothermocouples, one at the center of the container and the other alongthe periphery (one inch from the wall, and one inch from the bottom)were used as indicators of the carbon black sample temperature. Adetailed diagram is shown in FIG. 5.

The reactor was making carbon black of an STSA equivalent to V7H (˜112m²/g) since the heat treatment experiments were performed on V7H. Thegoal was to keep the quench extremely short to make a low spec 20 blackand then collect the hot-separated sample. Wet pellets and fluffysamples from the MUF were collected at the same time as control samples.Spec 20 is a reference to Toluene Discoloration (tested per ASTM D1618).

The main mechanism for the tail gas to get into the sampling tank was bydiffusion (since it was a dead end to the flow stream) and would notresult in significant PAH condensation. Thus, the experiment was carriedout without preheating the sampling system. The Spec 20 of the fluffysample from the MUF was brought down in the fifties, by moving thequench upstream which was finally at 2′9″ pointed upstream.

Table 3 shows PAH and other data for different samples. WP refers to wetpellet carbon black wherein the sample is taken prior to going to thedryer.

TABLE 3 PAH results on different samples. Data shown are average of twomeasurements. Total PAH Sample (ppm) comment Cyclone 16.3 1 hourcollection WP 1887.4 control MUF 970.6 control

PAH measured on MUF and WP samples were significantly higher than thatcollected in the cyclone via hot gas separation. The collection time wasan hour, and the PAH levels were about ˜16 ppm due to the fact that thesampling system was hot and at steady state separation temperature ofabout ˜700° C. for most of the sampling duration.

Table 4 shows the summary of results for, spec 20, PAH measurements andmajor compound properties relative to the MUF fluffy, which was thecontrol sample. The data shown in the table with asterisk is an averagevalue of two data points and the errors are also based on twomeasurements. It is clear from the results that, while the PAH on theblack was reduced by two orders of magnitude, the compound propertiesmeasured were equivalent, within experimental errors. The activehydrogen content measured by proton extraction, appear to be very closewhile the spec 20 and total PAH were very different between the cycloneand the control samples. This is indicative of the fact that, while thePAHs were removed (or not allowed to condense on the surface of black),the surface chemistry of the black remained unaffected (measured byactive H content) thus resulting in very similar compound properties.FIGS. 3 and 4 are graphical representations of measured PAH and compoundproperties, again showing that the removing the PAH by the abovedescribed method, does not affect the reinforcing properties of theblack.

TABLE 4 Sample MUF WP Cyclone Surface BET(m²/g) 113.3 116.2 120.2 AreaSTSA(m²/g) 108 111.4 110.2 I2 (mg/g) 113.8 105.7 121.4 Surface H content4020 3981 3827 Chemistry (ppm) SP20 (%) 42.0 62.3 94.5 PAH 22* 970.51887.5 16.0 (ppm) Rubber Bound 100.0 ± 1.5 102.2 ± 2.3 102.4 ± 0.8 Properties Rubber Relative to Elongation 100.0 ± 4.6  99.4 ± 3.3 97.7 ±1.8 MUF fluffy* at Break Tensile 100.0 ± 6.9  97.7 ± 4.0 98.9 ± 3.9Strength 300%/100% 100.0 ± 1.4 100.9 ± 1.2 100.0 ± 0.3  Moduli Ratio Tanδ max @ 100.0 ± 2.7 102.2 ± 1.9 97.3 ± 2.0 60° C., 10 Hz Abrasion 100.0± 1.6 103.2 ± 1.6 93.4 ± 5.3 Index (7% slip) Abrasion 100.0 ± 1.1 102.2± 1.1 102.2 ± 3.3  Index (14% slip) *Reported values and errors based ontwo tests

The side-stream sampling for hot gas separation of carbon black fromtail gas using cyclone was successful in reducing the PAH contaminationof carbon black by two orders of magnitude. After treatment of carbonblack can occur in a steam fluidized bed.

As an alternative, the MUFs can be replaced with filter houses havingceramic filters which can operate at temperatures of around 1000° C. Thehot carbon black then dropping out of the rotary lock, can be conveyedwith steam which in turn will also cool the carbon black to the requiredtemperature to be fed to the pelletizer, or it can be conveyed with coldtail gas after stripping it off of the PAHs. The tail gas thus availablefrom the process will have lot more recoverable energy; it will be “lesswet” since such a process would not require water spray in the venturicooler, and make the tail gas more conducive to recycle in the burner asfuel.

Example 4

In this example, Example 2 was repeated except different carbon blacks,as listed below in the tables were used and treated to remove PAHs.

CB Properties Typical STSA I2 PAH22 CB ID (m²/g) (mg/g) I/STSA (ppm)N299 Control A 97 108 1.11 70 N299 Extracted A 24 N121 Control A 114 1211.06 740 N121 Extracted A 95 N299 Control B 97 108 1.11 105 N299Extracted B 27 N121 Control B 114 121 1.06 530 N121 Extracted B 91

100 120 60 min @ 150° C. MOONEY SCORCH RPA Viscosity Scorch BOUND ts2time t′50 time t′90 time Min ML(1 + 4) ML(1 + RUBBER Sample Name (min)(min) (min) Torque Max Torque 24 Hrs. t5) (min) Ave (%) N299 Original A6.38 14.71 30.14 5.09 31.67 97.93 49.85 26 N121 Original A 5.51 12.8628.44 5.45 32.90 102.95 43.41 32 N299 Original B 6.97 15.16 30.92 4.9732.15 96.03 48.34 26 N121 Original B 6.27 14.11 31.15 5.51 32.51 103.2749.26 31 N299 Extracted A 6.39 14.35 30.25 5.03 31.67 94.65 48.79 27N121 Extracted A 5.99 13.65 31.00 6.01 33.62 102.04 43.76 32 N299Extracted B 7.14 15.30 31.73 4.94 31.85 92.01 48.80 26 N121 Extracted B6.33 14.34 31.52 5.49 32.43 101.27 49.21 30 N121 Extracted B 6.30 14.2631.59 5.48 32.50 100.68 48.60 31 N299 Extracted B 7.11 15.22 31.53 4.8931.72 92.65 48.77 25 N121 Extracted A 5.77 13.39 29.45 5.46 32.55 100.4445.37 31 N299 Extracted A 6.56 14.61 31.21 5.12 31.76 94.95 48.37 27N121 Original B 6.14 14.04 31.94 5.74 33.51 100.35 47.70 32 N299Original B 7.05 15.32 32.26 5.04 32.29 93.53 46.80 26 N121 Original A5.43 12.20 25.54 5.16 29.81 103.49 41.30 32 N299 Original A 6.40 14.3231.54 5.43 32.73 97.45 46.77 29

TENSILE Elongation 100% 200% 300% at Break Tensile 25% mod. 50% mod.mod. mod. mod. Sample Name (%) (Mpa) (Mpa) (Mpa) (Mpa) (Mpa) (Mpa) N299Original A 433 28.91 1.42 2.02 3.69 10.67 19.25 N121 Original A 41830.03 1.50 2.16 3.96 11.64 20.83 N299 Original B 411 27.92 1.44 2.113.95 11.08 19.51 N121 Original B 412 29.46 1.51 2.17 3.96 11.31 20.36N299 Extracted A 436 29.25 1.43 2.06 3.70 10.76 19.26 N121 Extracted A389 28.52 1.57 2.28 4.18 11.78 21.12 N299 Extracted B 416 27.92 1.402.01 3.72 10.67 18.96 N121 Extracted B 434 30.41 1.52 2.18 3.87 10.6519.56 N121 Extracted B 433 29.82 1.49 2.11 3.81 11.01 19.88 N299Extracted B 429 27.97 1.37 1.96 3.56 10.18 18.46 N121 Extracted A 40528.54 1.48 2.15 3.84 10.86 19.72 N299 Extracted A 434 29.14 1.45 2.103.77 10.29 18.61 N121 Original B 435 30.53 1.54 2.23 3.97 10.99 20.09N299 Original B 425 28.54 1.44 2.09 3.81 10.85 19.28 N121 Original A 43531.59 1.49 2.15 3.91 11.34 20.48 N299 Original A 433 30.48 1.46 2.093.84 11.13 20.05

ABRASION REBOUNDS HARDNESS REBOUNDS Wear Avg. R/T RT 70 oc Wear Avg.(Lab (Lab Index) Sample Name Avgs. Avgs. Avgs. Index) 14% Slip 21% SlipN299 Original A 42.1 70.8 50.3 145 152 N121 Original A 41.3 71.8 50.3155 168 N299 Original B 42.9 70.4 50.8 131 135 N121 Original B 40.8 71.049.3 156 160 N299 Extracted A 41.6 69.8 48.9 136 146 N121 Extracted A42.1 70.8 50.6 145 161 N299 Extracted B 42.3 69.6 49.7 120 133 N121Extracted B 41.2 70.9 50.6 150 153 N121 Extracted B 41.1 70.1 48.4 142154 N299 Extracted B 42.1 70.0 49.9 126 130 N121 Extracted A 41.8 70.549.3 140 159 N299 Extracted A 41.2 70.2 48.7 129 139 N121 Original B41.7 70.3 49.0 153 162 N299 Original B 41.4 70.8 50.0 129 133 N121Original A 42.1 71.9 49.6 151 157 N299 Original A 41.9 70.6 50.0 147 142

SWELLS SPECIFIC GRAVITY RHEOMETRICS Max Tan Swell Index DensiTECH MaxTan Delta @ Delta @ Sample Name Vr Ave Ave in H20 70° C. 0° C. N299Original A 0.23 2.01 1.1328 0.193 0.330 N121 Original A 0.23 2.01 1.12810.192 0.322 N299 Original B 0.23 2.01 1.1327 0.197 0.334 N121 Original B0.23 2.00 1.1307 0.199 0.355 N299 Extracted A 0.23 2.05 1.1325 0.2010.341 N121 Extracted A 0.23 1.98 1.1301 0.195 0.333 N299 Extracted B0.23 2.03 1.1318 0.204 0.341 N121 Extracted B 0.23 2.02 1.1325 0.2080.343 N121 Extracted B 0.23 2.03 1.1313 0.200 0.334 N299 Extracted B0.23 2.04 1.1327 0.201 0.337 N121 Extracted A 0.23 2.00 1.1280 0.1950.325 N299 Extracted A 0.23 2.00 1.1309 0.205 0.330 N121 Original B 0.231.97 1.1313 0.204 0.330 N299 Original B 0.23 2.01 1.1331 0.203 0.341N121 Original A 0.23 1.96 1.1282 0.198 0.333 N299 Original A 0.23 1.971.1330 0.196 0.334

Applicants specifically incorporate the entire contents of all citedreferences in this disclosure. Further, when an amount, concentration,or other value or parameter is given as either a range, preferred range,or a list of upper preferable values and lower preferable values, thisis to be understood as specifically disclosing all ranges formed fromany pair of any upper range limit or preferred value and any lower rangelimit or preferred value, regardless of whether ranges are separatelydisclosed. Where a range of numerical values is recited herein, unlessotherwise stated, the range is intended to include the endpointsthereof, and all integers and fractions within the range. It is notintended that the scope of the invention be limited to the specificvalues recited when defining a range.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the present specification andpractice of the present invention disclosed herein. It is intended thatthe present specification and examples be considered as exemplary onlywith a true scope and spirit of the invention being indicated by thefollowing claims and equivalents thereof.

1. A carbon black having a low PAH content, wherein the PAH content isdetermined based on a PAH22 content, said carbon black is a furnacecarbon black and has a STSA, I₂No/STSA ratio, and PAH content asfollows: a) STSA: 110-250 m²/g I₂No (mg/g)/STSA (m²/g): 1.20 to 0.70PAH: 400 ppm or less; or b) STSA: 80-110 m²/g I₂No (mg/g)/STSA (m²/g):1.15 to 0.70 PAH: 30 ppm or less; or c) STSA: 65-75 m²/g I₂No(mg/g)/STSA (m²/g): 1.10-0.88 PAH: 500 ppm or less DBP: 115-125 mL/100g; or d) STSA: 65-80 m²/g I₂No (mg/g)/STSA (m²/g): 0.70 to 0.88 PAH: 500ppm or less; or e) STSA: 1 to 35 m²/g I₂No (mg/g)/STSA (m²/g): 1.40 to0.70 PAH: 50 ppm or less; or f) STSA: 70 to 90 m²/g I₂No (mg/g)/STSA(m²/g): 1.00 to 1.20 PAH: 50 ppm or less DBP: 60-80 mL/100 g; or g)STSA: 87-95 m²/g I₂No (mg/g)/STSA (m²/g): 0.91 to 1.08 PAH: 100 ppm orless DBP: 109-119 mL/100 g, wherein said carbon black has one or more ofthe following mechanical properties or rubber properties when includedin a rubber formulation according to ASTM D 3191-02: abrasion resistance(21% slip) of from 80 to 170; elongation (%) of from 300 to 600; tensilestrength (Mpa) of from 20 to 35; 100% modulus (Mpa) of from 2.4 to 4.5;300% modulus (Mpa) of from 12 to 23; ratio of 300% modulus/100% modulus(M300%/M100%) of from 3.5 to 6; bound rubber (%) of from 15 to 30;and/or max tan delta @ 0° C. of from 0.25 to 0.4.
 2. The carbon black ofclaim 1, wherein said carbon black is a) and has an I₂No (mg/g)/STSA(m²/g) of 1.15 to 0.70.
 3. The carbon black of claim 2, wherein saidcarbon black has a STSA of 110 to 200 m²/g.
 4. The carbon black of claim2, wherein said carbon black has a STSA of 110 to 175 m²/g.
 5. Thecarbon black of claim 4, wherein said carbon black has a PAH content of1 ppm to 200 ppm.
 6. The carbon black of claim 4, wherein said carbonblack has a PAH content of 1 ppm to 50 ppm.
 7. The carbon black of claim4, wherein said carbon black has a PAH of 1 ppm to 150 ppm.
 8. Thecarbon black of claim 4, wherein said carbon black has a PAH content of1 ppm to 100 ppm.
 9. The carbon black of claim 4, wherein said carbonblack has a PAH of 20 ppm or less.
 10. The carbon black of claim 2,wherein said carbon black has a STSA of 110 to 150 m²/g.
 11. The carbonblack of claim 2, wherein said carbon black has a I₂No/STSA of 1.15 to0.9.
 12. The carbon black of claim 1, wherein said carbon black is b)and said I₂No/STSA is 1.10 or less.
 13. The carbon black of claim 12,wherein said PAH content is 1 ppm to 20 ppm.
 14. The carbon black ofclaim 12, wherein said PAH content is 10 ppm or less.
 15. The carbonblack of claim 1, wherein said carbon black is c).
 16. The carbon blackof claim 15, wherein said PAH content is 1 ppm to 100 ppm.
 17. Thecarbon black of claim 1, wherein said carbon black is d).
 18. The carbonblack of claim 17, wherein said PAH content is 1 ppm to 300 ppm.
 19. Thecarbon black of claim 17, wherein said PAH content is 1 ppm to 150 ppm.20. The carbon black of claim 17, wherein said PAH content is 1 ppm to100 ppm.
 21. The carbon black of claim 17, wherein said PAH content is 1ppm to 50 ppm.
 22. The carbon black of claim 17, wherein said PAHcontent is 20 ppm or less.
 23. The carbon black of claim 1, wherein saidcarbon black is e).
 24. The carbon black of claim 23, wherein said PAHcontent is 1 ppm to 20 ppm.
 25. The carbon black of claim 23, whereinsaid PAH content is 10 ppm or less.
 26. The carbon black of claim 1,wherein said carbon black is f).
 27. The carbon black of claim 26,wherein said carbon black has a DBP of 72 mL/100 g, an STSA of 76 m²/g,and an I₂No/STSA of 1.05 to 1.09, and PAH content of 50 or less.
 28. Thecarbon black of claim 26, wherein the DBP is 66-77 mL/100 g or less. 29.The carbon black of claim 26, wherein said DBP is 60 mL/100 g to 72mL/100 g.
 30. The carbon black of claim 26, wherein said PAH content is1 ppm to 20 ppm.
 31. The carbon black of claim 26, wherein said PAHcontent is 10 ppm or less.
 32. A method to produce the carbon black ofclaim 1, said method comprising subjecting or treating a carbon blackhaving a PAH content to/with sufficient heat, optionally in an inert orvacuum atmosphere, such that the PAH or a portion thereof is removed toform said carbon black.
 33. The method of claim 32, wherein said heat ison the order of from about 300° C. to about 950° C.
 34. A method toproduce the carbon black of claim 1, said method comprising subjecting acarbon black having a PAH above 500 ppm to one or more solventextractions.
 35. A method to produce the carbon black of claim 1,wherein during manufacturing of carbon black involving the presence ofhot tail gas containing a carbon black and PAH, said method comprisingremoving said hot tail gas with PAH from said carbon black.
 36. Themethod of claim 35, wherein said removing of said hot tail gas is at atemperature of from about 260° C. to about 950° C.
 37. The method ofclaim 35, wherein said removing of said hot tail gas is at a temperatureof from about 500° C. to about 900° C.
 38. The method of claim 35,wherein said carbon black is a furnace carbon black and said methodoccurs in a furnace carbon black reactor.
 39. The method of claim 35,wherein a cyclone is used to remove said hot tail gas from said carbonblack.
 40. The method of claim 35, wherein a high temperature filter isused to remove said hot tail gas from said carbon black.
 41. The methodof claim 35, wherein after separating said carbon black from said hottail gas, said carbon black has a carbon black temperature above 200°C., and said method further comprising lowering the carbon blacktemperature to below 200° C. prior to introducing said carbon black intoa bag filter.
 42. The method of claim 35, wherein after separating saidcarbon black from said hot tail gas, said carbon black has a carbonblack temperature above 400° C., and said method further comprisinglowering the carbon black temperature to below 400° C. prior tointroducing said carbon black into a bag filter.
 43. The method of claim35, wherein said PAH remains in a gas phase and does not condense ofsaid carbon black.
 44. The method of claim 43, wherein said recyclingcomprises re-using said hot tail gas in a carbon black manufacturingprocess.
 45. The method of claim 43, wherein said recycling comprisesre-using said hot tail gas as a heat source.
 46. The method of claim 45,wherein said hot tail gas is used as at least a partial heat source fora dryer.
 47. The method of claim 45, wherein said dryer is a carbonblack dryer.
 48. The method of claim 45, wherein said dryer is operatedat a sufficient temperature such that the PAH in said hot tail gas isdestroyed.
 49. The method of claim 35, further comprising recycling saidhot tail gas with PAH.
 50. The carbon black of claim 1, wherein saidcarbon black has a PAH content of from about 0.15 to about 2micrograms/m².
 51. The carbon black of claim 1, wherein said carbonblack is a rubber grade or tire grade carbon black.
 52. The carbon blackof claim 1, wherein said carbon black is a N110-N787 ASTM carbon black.53. A carbon black having a low PAH content, wherein the PAH content isdetermined based on a PAH22 content, said carbon black is a furnacecarbon black and has a STSA, I2No/STSA ratio, and PAH content asfollows: a) STSA: 110-250 m²/g I₂No (mg/g)/STSA (m²/g): 1.20 to 0.70PAH: 400 ppm or less; or b) STSA: 80-110 m²/g I₂No (mg/g)/STSA (m²/g):1.15 to 0.70 PAH: 30 ppm or less; or c) STSA: 65-75 m²/g I₂No(mg/g)/STSA (m²/g): 1.10-0.88 PAH: 500 ppm or less DBP: 115-125 mL/100g; or d) STSA: 65-80 m²/g I₂No (mg/g)/STSA (m²/g): 0.70 to 0.88 PAH: 500ppm or less; or e) STSA: 1 to 35 m²/g I₂No (mg/g)/STSA (m²/g): 1.40 to0.70 PAH: 50 ppm or less; or f) STSA: 70 to 90 m²/g I₂No (mg/g)/STSA(m²/g): 1.00 to 1.20 PAH: 50 ppm or less DBP: 60-80 mL/100 g; or g)STSA: 87-95 m²/g I₂No (mg/g)/STSA (m²/g): 0.91 to 1.08 PAH: 100 ppm orless DBP: 109-119 mL/100 g wherein said carbon black has the ability toimpart at least one mechanical property in a rubber matrix, or anelastomeric composition, said at least one mechanical property is one ormore of the following: abrasion resistance (21% slip)—, elongation(%)—ASTM D 3191-02 Standard Test Methods for Carbon Black in SBR—Recipeand Evaluation Procedures, tensile strength (Mpa); ASTM D 3191-02Standard Test Methods for Carbon Black in SBR—Recipe and EvaluationProcedures, 100% modulus (Mpa); ASTM D 3191-02 Standard Test Methods forCarbon Black in SBR—Recipe and Evaluation Procedures, 300% modulus(Mpa); ASTM D 3191-02 Standard Test Methods for Carbon Black inSBR—Recipe and Evaluation Procedures, ratio of 300% modulus/100% modulus(M300%/M100%); ASTM D 3191-02 Standard Test Methods for Carbon Black inSBR—Recipe and Evaluation Procedures, bound rubber (%); or max tan delta@ 0° C. tested with ARES/Rheometrics Dynamic Spectrometer II (RDS II,Rheometrics, Inc., N.J) operated in a torsion strain mode (shear) withmeasurements performed at 0° C. for strain sweeps with double strainamplitude (DSA) ranging from 0.2 to 120%, at a constant frequency of 10Hz, and wherein at least one of said mechanical properties for saidcarbon black is within 10% of the value for the same mechanical propertyfor the same type of carbon black having a PAH22 content of 600 ppm to1,000 ppm.